ARCHIVED REPORTS_XR0011499 - Laserfiche WebLink

Home Browse Search

ATC Associates Inc It 17 Lone Palm Avenue Suite B ( "%TCModesto California 95351 209-579-2221 ASSOCIATES INC fax 209-579-2225 BTEX utilizing EPA Method 802113, and oxygenate fuel additives including methyl tert-butyl ether (MTBE) utilizing EPA method 8260B I GROUNDWATER ELEVATION Water level measurements were collected from wells MW 1 through MW7 on October 6, 2004 Depth to water ranged from 57 50 feet below ground surface (bsg) to 58 31 feet bsg Water elevations ranged from a high of—34 14 to a low of—34 46 representing an average decrease in water table elevation of 2 62 feet since July 8, 2004 The water level data were used to develop a groundwater elevation contour map (Figure 3) Review of the groundwater elevation contour map indicates that the hydraulic gradient beneath the site on October 6, 2004, was approximately 0 005 foot per foot or approximately 26 feet per mile and the gradient direction was generally to the southwest (Figure 3) A summary of groundwater monitoring data is presented in Table I ANALYTICAL RESULTS Chemicals of Concern (COCs) were only detected in the groundwater samples collected from MWI and MW2 Benzene was detected in the groundwater sample collected from MW2 at a concentration of 4 2 µg/L TPHg was detected in the groundwater sample collected from NIW1 and MW2 at concentrations of 55 µg/L and 71 µg/L, respectively MTBE was detected in the groundwater samples collected from MW 1 and MW2 at concentrations of 7 2 µg/L and 13µg/L, respectively Groundwater samples collected from wells MW3, MW4, MW5, MW6, and MW7 did not contain concentrations of TPHg, TPHd, TPHk, BTEX constituents, or fuel oxygenates at or above the laboratory reporting limits Groundwater samples collected from wells MWi through MW7 did not contain concentrations of TPHd or TPHk, and have not since March 27, 2001 Analytical results for groundwater samples are contained in Table 2 Laboratory data sheets and chain-of-custody documentation are contained in Attachment 2 GEOTRACKER DATA UPLOAD The site facility global ID number is T0607700242 The depth to water data was submitted electronically to the State Water Resources Control Board (SWRCB) Geotracker database (confirmation number 2891067326) and the laboratory data was also submitted electronically to the SWRCB Geotracker database (confirmation number 8045782744) Documentation of the data submittal is contained in Attachment 3 I S 162577\4QR-2004 doe 3